[1] Fast Castle, in its heyday, comprised a courtyard and keep, built on a narrow sloping plateau, 27 by 82 metres (89 by 269 ft), on an eponymous promontory overlooking the North Sea.

There is evidence of Iron Age habitation here, and it was centrally positioned in the British kingdom of Bryneich, and its Anglo-Saxon successor state of Bernicia.

During the "Rough Wooing" of Scotland by Henry VIII, the castle was captured again by the English in 1547, but was back in Scottish hands by the time of Mary, Queen of Scots' stay here in 1566.

[3] Fast castle was well armed: some of the guns were taken to Berwick on Tweed during the English intervention against the supporters of Mary, Queen of Scots in the 1570s.

[7] Sir Robert Logan was a notorious dissolute and "ne'er do well" who was implicated in the Gowrie conspiracy to kidnap the young King James VI.

In 1594, Logan contracted with the famed mathematician (and supposed wizard) John Napier to search Fast Castle for treasure.

Shipmasters would see the lights while travelling in darkness, and consider that they had reached a safe haven, only to find that they had been guided on to rocks, where wrecking parties awaited for plunder.

[citation needed] The castle is thought to have inspired Sir Walter Scott's description of the fictional "Wolf's Crag", which features in his 1819 novel The Bride of Lammermoor.

[10] Fast Castle and Logan of Restalrig both appear in Nigel Tranter's trilogy of historical novels, The Master of Gray series.